Pressure limiting washer assembly



y Feb. 20, 1945.

.II-lll l 0 Inventor Z e e Sja @meer 9 By uw and W I, f W W. W

@16% WW l Feb. 20, 1945. SPENCER- v 2,369,865

4 PRESSURE LIMI'IIING WASHER ASSEMBLY Filed Feb. 15, 194s 2 shets-sheet2 Petented Feb. 2o, 1945 UNITED STATES PATENT OFFICE PRESSURE LIMITINGWASHER ASSEMBLY Lee Spencer, Jamaica, N. Y.

Application February 13, 1943, Serial No. 475,830

4 Claims.

I'his invention relates to a novelmethod and means for bolting andsecurely clamping companion or complementa] members together, and hasparticular reference to a pressure limiting washer assembly which isexpressly, but not necessarily, applicable to rail fasteners, forinstance, the type employing conventional sh plates assembled and heldin place by regular or customary bolts and nuts.

My invention constitutes means embracing the shank of the bolt andinterposed' between the nut and adjacent work part and expresslydesigned to be actuated by the nut pressure to limit the inward clampingfeed motion of said nut and to in this manner precautiously andmechanically prevent both over-tightening and undertightening of saidnut. I

Under present day conditions, and as nuts are generally used, thetension applied to the bolt is governed by the degree of torque appliedto the nut. This torque may be moderate or extreme, according to the fitof the nut on the threads f the bolts, tight threads producing a hardturning nut, loose threads an easy turning nut. An equal pressureapplied in tightening these two varieties results in limited tension inthe bolt with the hard turning nut, and the reverse with the easyrunning nut, that is, high bolttension.

These observations in the fields are actual, there now being nopractical means of insuring uniform bolt tension. It is essential,however,V

that these bolts have uniform tension. Tests made show that with boltstightened by machine with an adjustment on the machine to insure uniformtorque on the nut, bolt tensionvaried Y from 4,000 pounds to 24,000pounds instead of the desired 12,000 pounds.

When these bolts are tightened in by hand wrenches, about the samevariation of results are.

obtained as a workman tightens with the wrench until he feels a certainstrain and considers it a good job, but as he has exerted his strengthon the threads only, it is found that with poor hard working threadshardly any bolt tension exists and on the free running bolts, too muchpresents itself.

Briefly, the invention hereinafter comprehended is to disregard thetorsion entirely, this by employing pressure limiting spring washermeans to obtain the tension desired.

Other features and advantages of the invention will become more readilyapparent from the following description and the accompanyingillustrative drawings.

In the drawings, wherein like numerals are employed to designate likeelements and parts throughout the same:

Figure 1 is a transverse or cross-sectional view through track railsections, adjoining nsh plateson opposite sides thereof, there beingshown, in elevation, a conventional bolt and nut, and the especiallydesigned washer representing the preferred embodiment ofthe invention.

Figure2 is a detail enlarged elevational view looking at thenut-equipped end of the bolt and bringing out the construction of thenovel nut checking washer seen in Figure 1.

Figure 3 is a section on the line 3--3 of Figure 2.

Figure 4 is aview like Figure 3 showing a concavo-convex washer in theposition before it is forced into the active position seen in Figure 3.

Figure 5 is a detail view of the concavo-convex washer per se.

Figure 6 is a View partly in section and partly in elevation showing ailsh plate, threaded boltshank, nut and a diierent form or modifiedstyle of washer before it is` compressed to nut-checking position.

Figure 7 is a view like Figure 6 showing the nut threaded home with thewasher in its ilnal y position.

Figure 8 is an elevational view of the style of the washer seen inFigure 6, showing only the washer.

Figure 9 is a fragmentary elevational and sectional view of a furthermodification employing .companion washers and showing these in theirnon-active or inert positions. y

Figure 10 is a view like Figure 9, showing the nut tightened up and thecoacting washers assuming their ,stop-nut positions.

By way of introduction to the detailed description, I desire itunderstood that the structural means available for achieving the resultsunder advisement is and will be variable in basic characteristics.

One form or species of the invention is covered in Figures 1 to 5,inclusive, a second in Figures 6 to 8, inclusive, and a third in Figures9 and 10. These will be separately described for* a clear comprehensionof the invention.

Reference being had yto Figures 1 to 5, inclusive, the track, generallymade up of rail sections,

is denoted by the reference character A, the sh' carrying the clampingnut E, the head F bearing against one of the fish plates. It is themeans I I with which we are principally concerned.

Specifically, the above means II (Figs. l to 5, inclusive) comprises aspring steel washer I2 of appropriate diameter in relation to themarginal dimensions of the nut E. This washer, as seen in Figure 4, isconcavo-convex in its natural or unbent form. It is provided atequi-distant, circumferentially spaced points with struck-out tonguesfunctioning as detents I3. It is to -be noted that there is a short slitI4 on the outer peripheral side and a longer slit I5 on the opposite orinner peripheral side, the slit I5 thus being in a region toward thecentral shankaccommodating hole or aperture of the washer. 'This iscalculated to cause the detents to spring outwardly with their inneredges I5 Iadjacent to the marginal edges of the nut, as brought out toadvantage in Figure 2. Under this predetermined arrangement the edges ofthe tongues thus presented to the nut are such as to definitely seizesaid nut and to prevent further turning in a direction toward thewasher, that is, when the washer is flattened and pressed upon to thedesired degree predetermined by the manufacturer. This canting ortilting feature of the detent tongues is important, as is obvious from acareful consideration of Figure 2. There is another and auxiliary tongueI6 struck out from the washer, but this lis on the outer perimeter ormarginal edge. Moreover, it is laterally bent inwardly, that is, in adirection toward the sh plate or other element with which it cooperates.purpose of this element I6 is its ability to serve as a tongue tofiguratively dig into the surface of the Work and lock the washer sothat the washer is prevented from turning in relation to the nut and thework, and so that the detents will spring quickly into their respectiveholding positions. It will thus be seen that we have here a simpleWasher, circumferentially spaced, struckout tongues functioning asdetents, the tongues being of special design andfthere being a dog orequivalent anti-slipping tongue I 6 to serve as just described.

Reference is now directed to Figures 6, '7 and 8. Here the check meansI1 is, again, in the form of a washer I8. But `this is a split washer.It will be noted that at predetermined points the washer is arched intoarcuate bends I9 andfat circumferentially spaced points i between thebends there are indentations 20 pressing against the fish plates in themanner brought out in Figure 6. These features I9 and 20, collectivelyspeaking, serve to render the washer more sensi- Thel tive and thusquickly responsive to perform the desired function. It is to be notedthat on opposite sides of the slit vare two lugs 22 and 23,respectively. The lug 22 in relation to side elevational picturizationof the washer, is directed out-` wardly so las to be in a position toquickly seize the edge portion of the nut when the desired pressure ofthe nut against the washer is reached.

On the other hand, the complemental tongue 23A by the numeral 24. Asbrought out advantageously in Figure 9, there are two washers hereemployed, the compressible rubber washer 25 being a sort of a selfconforming ller, and the spring metal washer 26 is like the washer I2,except that it is flat instead of concave-convex. That is to say, thewasher 26 has pressure responsive tongues forming snap-action detents21. Here the detents are pressed into nut-retaining position by therubber washer. Referring to Figure 9, and then to Figure 10, it will beseen that as the nut is turned home, the rubber washer is squeezed orcompressed and portions thereof attempting to find an outlet, projectthemselves into the openings defining the detents or tongues 21. Thus,the tongues are pressed and jut out quickly and grippingly engage thenut to stop the rotation in a manner already described. Manifestly, allparts will have to be carefully and scientifically manufactured in orderto insure the desired cooperative and coinciding functions.

Thus, it will be seen that although there are other ways and means ofaccomplishing the same basic result, the three embodiments illustratedare, apparently, suillciently comprehensive `to enable the reader tounderstand the invention and the extensive nature thereof in so far asscope is concerned.

As long as bolts and threaded nuts have been used to join and fasten twoor more elements or members together, it has been recognized thatprovision must be made for some sort of spring washer or equivalent partbetween the bolt and the nut to take up the slack caused by wear, andmaintain tension between the held parts to prevent the nut from backingoff the threads on the bolt.

I have noted that there was a real need for more than this and presumethe same need exists in other fields. On the railroad, rail joints aregenerally bolted together with fish plates and bolts incorporating theaforesaid washers to keep the slack out of the parts which are boltedtogether in the conventional manner. But it can be seen, from practicalresults, that these spring washers do not perform as intended; somebolts being over-tightened and tending to freeze these parts together,that were designed to be held only so tightly together that there wouldbe free movement of these parts longitudinally due to allowance forproper expansion; others were held together so loosely that weardeveloped very quickly.

Tests, as well as observation, showed that all these devices wereconstructed onthe principle that a certainl pressure applied in turningup the nut governed the amount of tension in the bolt. In short, thetorsion applied to the nut was the determining factor as to how tightthese parts were held in relation to each other. If a hard turning nutwas used, little tension was created, and if a free nut was used, asmall amount of torsion created equal tension. I made several trials ofdifferent ways to get a uniform result, all of these being based on thesame principle,

that a spring filler of some kind be used between the nut and the faceof the held part, this spring filler being so shaped and manufacturedthat after a predetermined pressure or tension was developed, it wouldbe impossible to further tighten the nut beyond this predetermined pointregardless of the torsion applied to the nut or just exactly oppositeall these other attempts.

All previous attempts seemed to take it for granted that there would beuniform tension applied to a bolt if uniform torsion was applied to thenut. There were numerous devices that depended on visual observation toshow when a certain tension was reached, such as washers which flattenedout to a flat plane when under certain compression, but nothing thatprevented further tightening beyond that point. l

I have attempted to, and think succeeded in, getting away from the humanelement with my devices inasmuch as at some point that is built intothese devices the nut is stopped with a positive stop preventingtightening beyond the desirable point and in this way overcoming theshortcomings of all these otherz'nut locks or Washers which cannot anddo not attempt this and can nd no reference to this problem anywhere orattempts to get results such as I claim.

It is thoughtthat persons skilled in the art to which the inventionrelates will be able to obtain a* clear understanding of the inventionafter considering the description in connection with the drawings.Therefore, a more lengthy description is regarded as unnecessary.

Minorchanges in shalpe, size and rearrangement of details coming withinthe field of invention claimed may be resorted to in actual practice, ifdesired.

I claim:

1. Washer means for use under a nut to limit bolt Vtension due totightening, comprising a spring metal washer of disc shape with means toavc-id slipping between the washer and work, the washer having'detentsnormally out of gripping contact with the nut, 4but which are deflectedto.

ward the nut to engage the perimeter thereof by predeterminedreactivepressure due to tightening the nut on the bolt, to preventfurther tightening.

2. A washer assembly for-use under a nut to limit bolt tension due totightening, consisting of two companion washers, one of non-metallicresilient material and the other of substantially at spring metal havingspaced tongues normally in the plane of the washer, but which aredeflected toward the nut to engage the surface thereof, by predeterminedreactive pressure of the resilient washer due to tightening the nut onthe bolt, to prevent further tightening.

3. A washer, for use under a nut to limit bolt tension due totightening, of spring metal and concavo-convex shape having tonguesarranged at spaced points normally lying in the surface of the washerand a work engaging tongue extending outwardly from the concavo side,the rst tongue to be deiiected toward the nut to engage the surfacethereof, when the Washer is flatftened to a point corresponding to apredetermined pressure, to prevent further tightening.

4'. A washer, for use under a nut to limit bolt tension due totightening, of spring metal, ra-

